there was a similar article in the WSJ recently but they hide them behind the paywall
https://www.nytimes.com/2023/03/01/travel/frugal-travel-airline-auctions.html
couldn't get behind that paywall, but the Points Guy recently did a similar article here are their rules (sorry, there is math)
Use ExpertFlyer or a similar tool to see how many premium class seats are still available on your flight.
Follow this equation for a bid price: Calculate the regular cost of a business class seat. Subtract what you paid for the economy fare, and aim for around 20% to 40% of the remaining price.
Bid slightly above the minimum to beat the crowd, since most people will choose the minimum.
https://thepointsguy.com/guide/guide-bidding-flight-upgrades/